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Pacheco-Vázquez F Caballero-Robledo GA Solano-Altamirano JM Altshuler E Batista-Leyva AJ Ruiz-Suárez JC 《Physical review letters》2011,106(21):218001
An object falling in a fluid reaches a terminal velocity when the drag force and its weight are balanced. Contrastingly, an object impacting into a granular medium rapidly dissipates all its energy and comes to rest always at a shallow depth. Here we study, experimentally and theoretically, the penetration dynamics of a projectile in a very long silo filled with expanded polystyrene particles. We discovered that, above a critical mass, the projectile reaches a terminal velocity and, therefore, an endless penetration. 相似文献
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R. Cartas-Fuentevilla A. Escalante-Hernandez J. A. Lopez-Osio J. M. Solano-Altamirano J. F. Tlapanco-Limon J. Berra-Montiel P. Enriquez-Silverio 《General Relativity and Gravitation》2011,43(5):1365-1390
We prove that some basic aspects of gravity commonly attributed to the modern connection-based approaches, can be reached
naturally within the usual Riemannian geometry-based approach, by assuming the independence between the metric and the connection
of the background manifold. These aspects are: 1) the BF-like field theory structure of the Einstein–Hilbert action, of the
cosmological term, and of the corresponding equations of motion; 2) the formulation of Maxwellian field theories using only
the Riemannian connection and its corresponding curvature tensor, and the subsequent unification of gravity and gauge interactions
in a four dimensional field theory; 3) the construction of four and three dimensional geometrical invariants in terms of the
Riemann tensor and its traces, particularly the formulation of an anomalous Chern–Simons topological model where the action of diffeomorphisms is identified with the action of a gauge symmetry, close
to Witten’s formulation of three-dimensional gravity as a Chern–Simon gauge theory. 4) Tordions as propagating and non-propagating fields are also formulated in this approach. This new formulation collapses to the usual
one when the metric connection is invoked, and certain geometrical structures very known in the traditional literature can
be identified as remanent structures in this collapse. 相似文献
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Monterrosas-Pérez Lorena Sandoval-Lira Jacinto Amador-Ramírez M. P. Flores-Segura H. Hernández-Pérez Julio M. Solano-Altamirano J. M. 《Structural chemistry》2020,31(1):305-317
Structural Chemistry - It is not frequent that weak non-covalent interactions counteract moderate hydrogen bonds. And it is also very uncommon to observe two concurrent n → π∗... 相似文献
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Carlos Medel-Portugal Juan Manuel Solano-Altamirano Jos Luis E. Carrillo-Estrada 《Entropy (Basel, Switzerland)》2021,23(3)
We propose a novel framework to describe the time-evolution of dilute classical and quantum gases, initially out of equilibrium and with spatial inhomogeneities, towards equilibrium. Briefly, we divide the system into small cells and consider the local equilibrium hypothesis. We subsequently define a global functional that is the sum of cell H-functionals. Each cell functional recovers the corresponding Maxwell–Boltzmann, Fermi–Dirac, or Bose–Einstein distribution function, depending on the classical or quantum nature of the gas. The time-evolution of the system is described by the relationship , and the equality condition occurs if the system is in the equilibrium state. Via the variational method, proof of the previous relationship, which might be an extension of the H-theorem for inhomogeneous systems, is presented for both classical and quantum gases. Furthermore, the H-functionals are in agreement with the correspondence principle. We discuss how the H-functionals can be identified with the system’s entropy and analyze the relaxation processes of out-of-equilibrium systems. 相似文献
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